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*CIL – Cell Image Library accession number. Please use this to reference an image.

CIL:34741*  Cite 

High resolution image showing that one parasomal sac lies anterior to each basal body of the somatic ciliature. A parasomal sac is an indentation of the plasma membrane that penetrates into the cytosol past the alveolus. Most sacs end as a coated pit. However, as seen in this micrograph, they can also give rise to more extensive tubules and vesicles. These vesicles pinch off into the cytosol to become early endosomes in a process called endocytosis where they lose their coat and fuse with a flattened smooth-membraned cisterna that is the early endosome. TEM taken on 7/17/67 by R. Allen with Philips 200 operating at 60kV. Neg. 9,000X. The raw film was scanned with an Epson Perfection V750 Pro. This image is best used for quantitative analysis.

Technical Details

Standard glutaraldehyde fixation followed by osmium tetroxide, dehydrated in alcohol and embedded in an epoxy resin. Microtome sections prepared at approximately 75nm thickness. Additional information available at (

Biological Sources
NCBI Organism Classification
Tetrahymena pyriformis
Cell Type
cell by organism
eukaryotic cell
Eukaryotic Protist
Ciliated Protist
Cellular Component
cell cortex
coated pit
plasma membrane
Richard Allen (University of Hawaii)
Digital Object Identifier (DOI)
Archival Resource Key (ARK)
Grouping This image is part of a group.
Image Type
transmission electron microscopy (TEM)
illumination by electrons
Image Mode
detection of electrons
Parameters Imaged
electron density
Source of Contrast
stain with broad specificity
Visualization Methods
stain with broad specificity
osmium tetroxide
uranyl salt
lead salt
Processing History
recorded image
unprocessed raw data
Data Qualifiers
raw, unprocessed data
suitable for spatial measurements
Spatial Axis Image Size Pixel Size
X 5988px 1.67nm
Y 4898px 1.67nm